Herbicidal compositions

ABSTRACT

A method for controlling the growth of weeds at a locus which comprises applying to the locus an effective amount of: (a) a urea herbicide of general formula (1); and (b) 2-(2′-nitro-4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione or an agriculturally acceptable salt or metal complex thereof.

This invention relates to new herbicidal compositions comprising amixture of a benzoyl cyclohexanedione and herbicidal urea compounds. Italso relates to the use of the mixture per se and to a method ofcontrolling weeds.

Herbicidal benzoyl cyclohexanediones are disclosed in the literature,for example European Patent Publication No. 0186118. In particular, U.S.Patent Publication No. 5,506,196 discloses2-(2′-nitro4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione. Ureaherbicides are well known in the literature. Examples of such herbicidesinclude as fenuron, fluometuron, monuron and monolinuron, chlortoluron,isoproturon, diuron, linuron, neburon, methabenzthiazuron andtebuthiuron, all of which are described in “The Pesticide Manual”, 12thedition, year 2000, and earlier editions (British Crop ProtectionCouncil).

The present invention provides a method for controlling the growth ofweeds (i.e. undesired vegetation) at a locus which comprises applying tothe locus an effective amount of:

(a) a urea herbicide, preferably a compound of the general formula (I):

R¹¹N(R¹²)CON(R¹³)R¹⁴  (I)

wherein R¹¹ represents an optionally substituted cyclic hydrocarbyl(which is preferably aromatic e.g. phenyl) or aromatic heterocyclyl(e.g. thiadiazol-2-yl) group, R¹² represents hydrogen or straight orbranched chain alkyl containing from 1 to 6 carbon atoms, R¹³ representsstraight or branched chain alkyl containing from 1 to 6 carbon atoms oran optionally substituted cyclic hydrocarbyl (e.g. 2-methylcyclohexyl)group and R¹⁴ represents hydrogen or straight or branched chain alkyl oralkoxy containing from 1 to 6 carbon atoms; and

(b) a benzoyl cyclohexanedione of formula (II):

which is 2-(2′-nitro-4′-methylsulfonylbenzoyl)-1,3cyclohexanedione or anagriculturally acceptable salt or metal complex thereof.

The urea herbicide and (b) are normally used in the form of herbicidalcompositions (i.e. in association with compatible diluents or carriersand/or surface-active agents suitable for use in herbicidalcompositions), for example as hereinafter described.

Preferred compounds of general formula I are those wherein R¹²represents the hydrogen atom or the methyl group and R¹³ represents themethyl group.

Preferred compounds of general formula I are those wherein R¹²represents the hydrogen atom, R¹³ represents a phenyl,3-trifluoromethylphenyl or 4-chlorophenyl group and R¹⁴ represents themethyl group;

or (b) R¹¹ represents a 4-chlorophenyl group and R¹⁴ represents themethoxy group, which are known respectively as fenuron, fluometuron,monuron and monolinuron, and more especially compounds of generalformula I wherein R¹² represents the hydrogen atom and R¹³ representsthe methyl group and (c) R¹¹ represents a 3-chloro-4-methylphenyl or4-isopropylphenyl group and R¹⁴ represents the methyl group;

or (d) R¹¹ represents the 3,4-dichlorophenyl group and R¹⁴ representsmethyl, methoxy or butyl; or (e) R¹¹ represents the benzothiazol-2-ylgroup, R¹² represents methyl and R¹³ represents methyl and R¹⁴represents hydrogen or (f) R¹¹ represents 5t-butyl-thiadiazol-2-yl; R¹²and R¹³ represent methyl and R¹⁴ represents hydrogen; which are knownrespectively as chlortoluron, isoproturon, diuron, linuron, neburon,methabenzthiazuron and tebuthiuron.

Preferably (a) is tebuthiuron.

In this description the term “agriculturally acceptable salts” meanssalts the cations or anions of which are known and accepted in the artfor the formation of salts for agricultural or horticultural use.Preferably the salts are water-soluble. Suitable salts with basesinclude alkali metal (e.g. sodium and potassium), alkaline earth metal(e.g. calcium and magnesium), ammonium and amine (e.g. diethanolamine,triethanolamine, octylamine, morpholine and dioctylmethylamine) salts.Suitable acid addition salts, formed by compounds containing an nitrogenatom with an available lone pair, include salts with inorganic acids,for example hydrochlorides, sulphates, phosphates and nitrates and saltswith organic acids, for example acetic acid.

The amounts of the urea herbicide and (b) applied vary with the natureof the weeds, the compositions used, the time of application, theclimatic and edaphic conditions and (when used to control the growth ofweeds in crop-growing areas) the nature of the crops. When applied to acrop-growing area, the rate of application should be sufficient tocontrol the growth of weeds without causing substantial permanent damageto the crop. In general, taking these factors into account, applicationrates of from about 500 g and 2500 g of the urea herbicide and fromabout 0.5 g to about 512 g of (b) per hectare give good results.However, it is to be understood that higher or lower application ratesmay be used, depending upon the particular problem of weed controlencountered.

The urea herbicide and (b) in combination may be used to controlselectively the growth of weeds, for example to control the growth ofthose species hereinafter mentioned, by pre- or post-emergenceapplication in a directional or non-directional fashion, e.g. bydirectional or non-directional spraying, to a locus of weed infestationwhich is an area used, or to be used, for growing crops, for examplecereals, e.g. wheat, barley, oats, rye, maize and rice, soya beans,field and dwarf beans, peas, lucerne, cotton, peanuts, flax, onions,carrots, oilseed rap, sunflower, and permanent or sown grassland beforeor after sowing of the crop or before or after emergence of the crop.For the selective control of weeds at a locus of weed infestation whichis an area used, or to be used, for the growing of crops, e.g. the cropshereinbefore mentioned, application rates of from about 500 g and about2500 g of the urea herbicide and from about 5 g to about 512 g of (b)per hectare are particularly suitable.

The method described above may be used to control a very wide spectrumof annual broad-leafed weeds and grass weeds. Examples of weeds whichmay be controlled include:

broad-leafed weeds, for example, Abutilon theophrasti, Amaranthushybridus, Amaranthus retroflexus, Amaranthus rudis, Amaranthustuberculatos, Ambrosia artemisilfolia, Ambrosia trifida, Bidens pilosa,Chenopodium album, Convolvulus arvensis, Datura ferox, Daturastramonium, Euphorbia spp, Galium aparine, Helianthus spp, Ipomoea spp.e.g. Ipomoea purpurea, Larnium spp, Matricaria spp, Plantago spp,Polygonum aviculare, Polygonum pennsylvanicum, Raphanus raphanistrum,Schkuhria pinnata, Sesbania exaltata, Sida rhombifolia, Sida spinosa,Sinapis arvensis, Solanum nigrum, Veronica hederaefolia, Veronicapersica, and Xanthium strumarium, and grass weeds, for exampleAlopecurus myosuroides, Avena fatua, Brachiaria plantaginea, Cenchrusechinatus, Cynodon dactylon, Digitaria horizontalis, Digitariasanguinalls, Echinochloa crus-galli, Eragrostis virescens, Sorghumbicolor, Eleusine indica, Imperata cylindrica, Panicum dichotomiflorum,Panicum maximum, Panicum miliaceum, Pennisetum glaucum, Setaria spp,e.g. Setaria faberii, Setaria viridis, Setaria lutescens and Setariaitalica, Sorghum halepense, and sedges, for example, Cyperus esculentus.

Where the locus is an area used, or to be used, for the growth of cerealcrop preferably the urea herbicid is isoproturon or chlorotoluron.

Where the locus is an area used, or to be used, for the growth ofsugarcane, or for total weed control, the urea herbicide is preferablytebuthiuron.

The following table summarizes dose rate of the components generally andpreferably in the method of the invention (all dose rates are in grammesper hectare (g/ha):

Most pre- Com- Tim- More fer- ponent Crop ing General Preferredpreferred red (b) sugar- pre- 50-150  75-150 75-150 100 cane em (b)sugar- post- 50-150  75-100 75-100 100 cane em Tebu- sugar- pre/500-1500 1000-1500 1000 1000 thiuron cane post (b) Total pre/ 75-200100-150 100-150  — post Tebu- Total pre/ 500-2500  100-2000 1500 —thiuron post (b) Cereal pre- 50-200 100-200 150 — em (b) Cereal post-50-100  50-100 75 — em Isopro- Cereal pre/ 750-2500 1000-2000 1500 —turon post Chlor- Cereal pre/ 1000-2000  1200-1600 1400 — toluron post

Where the method of the invention is used for the control of weeds at acereal locus in a preferred embodiment (especially where (a) isisoproturon or chlortoluron) a third herbicide is provided, preferablyselected from bifenox, diflufenican. When the locus is sugarcane(especially where (a) is tebuthiuron) preferred third partners includediuron and ametryne Preferred combinations include the following:

(i) from 1000 to 1500 g/ha of (a) (preferably from 1400 to 1500 g/ha);from 50 to 75 g/ha of (b) and from 100 to 150 g/ha of diflufenican;

(ii) from 1000 to 1500 g/ha of (a) (preferably about 1000 g/ha); from 50to 75 g/ha of (b) and from 100 to 150 g/ha of diflufenican;

(iii) from 1000 g/ha of (a); from 100 to 150 g/ha of (b); and from 1000to 1500 g/ha (preferably about 1250 g/ha) of diuron or ametryne.

The invention also provides herbicidal compositions comprising:

(a) a urea herbicide, preferably a compound of the general formula (I)above; and

(b) 2-(2′-nitro4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione or anagriculturally

acceptable salt or metal complex thereof;

in association with an agriculturally acceptable diluent and/or carrier.

Generally the active ingredients are homogeneously dispersed in othercomponents cited hereinafter, such as a diluent or carrier and/orsurface-active agents.

The term “herbicidal compositions” is used in a broad sense, to includenot only compositions which are ready for use as herbicides but alsoconcentrates which must be diluted before use. Preferably thecompositions contain from 0.05 to 90% by weight of (a) and (b).

Unless otherwise stated, the percentages and ratios appearing in thespecification are by weight

Generally a composition in which the ratio of (a):(b) is from 1:1 to5000:1 wt/wt of (a):(b) is used, proportions from 1:1 to 500:1 wt/wtbeing preferred.

The herbicidal composition may contain solid and liquid carriers andsurface-active agents (e.g. wetters, dispersants or emulsifiers alone orin combination). Surface-active agents that may be present in theherbicidal compositions of the present invention may be of the ionic ornon-ionic types, for example sulphoricinoleates, quaternary ammoniumderivatives, products based on condensates of ethylene oxide with nonyl-or octyl-phenols, or carboxylic acid esters of anhydrosorbitols whichhave been rend red soluble by etherification of the free hydroxy groupsby condensation with ethylene oxide, alkali and alkaline earth metalsalts of sulphuric acid esters and sulphonic acids such as dinonyl- anddioctyl-sodium sulphono-succinates and alkali and alkaline earth metalsalts of high molecular weight sulphonic acid derivatives such as sodiumand calcium lignosulphonates. Examples of suitable solid diluents orcarriers are aluminium silicate, talc, calcined magnesia, kieselguhr,tricalcium phosphate, powdered cork, absorbent carbon black and clayssuch as kaolin and bentonite. Examples of suitable liquid diluentsinclude water, acetophenone, cyclohexanone, isophorone, toluene, xylene,and mineral, animal, and vegetable oils (these diluents may be usedalone or in combination).

Herbicidal compositions according to the present invention may alsocontain, if desired, conventional adjuvants such as adhesives,protective colloids, thickeners, penetrating agents, stabilisers,sequestering agents, anti-caking agents, colouring agents and corrosioninhibitors. These adjuvants may also serve as carriers or diluents.

Preferred herbicidal compositions according to the present invention arewettable powders or water dispersible granules. Most preferredherbicidal compositions are aqueous suspension concentrates.

The wettable powders (or powders for spraying) usually contain from 20to 95% of combination, and they usually contain, in addition to thesolid vehicle, from 0 to 5% of a wetting agent, from 3 to 10% of adispersant agent and if necessary, from 0 to 10% of one or morestabilisers and/or other additives such as penetrating agents, adhesivesor anti-caking agents and colourings.

The aqueous suspension concentrates, which are applicable by spraying,are prepared in such a way as to obtain a stable fluid product (by finegrinding) which does not settle out and they usually contain from 10 to75% of combination, from 0.5 to 15% of surface acting agents, from 0.1to 10% of thixotropic agents, from 0 to 10% of suitabie additives suchas antifoams, corrosion inhibitors, stabilisers, and water or an organicliquid in which the active substance is sparingly soluble or insoluble.Some organic solid substances or inorganic salts can be dissolved inorder to assist in preventing sedimentation or as antifreeze for thewater.

Herbicidal compositions according to the present invention may alsocomprise (a) and (b) in association with, and preferably homogeneouslydispersed in, one or more other pesticidally active compounds and, ifdesired one or more compatible pesticidally acceptable diluents andcarriers, surface active agents or conventional adjuvants ashereinbefore described.

Pesticidally active compounds and other biologically active materialswhich may be included in, or used in conjunction with, the herbicidalcompositions of the present invention, for example those hereinbeforementioned, and which are acids or bases, may, if desired, be utilized inthe form of conventional derivatives, for example alkali metal and aminesalts and esters.

The compositions of the invention may also contain safeners which may beuseful to reduce the phytotoxicity of one or more of the pesticidallyactive compounds on a crop (generally where the partner pesticide is aherbicide).

The following examples illustrate herbicidal compositions for useaccording to the present invention. The following trade marks appear inthe examples: Arkopon, Arylan, Attagel, Rhodorsil, Solvesso, Soprophor,Sopropon, Synperonic and Tixosil. The Combination listed in thefollowing examples refers to the combination of a urea herbicide ofgeneral formula (I) and2-(2′-nitro4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione.

EXAMPLE C1

A suspension concentrate is formed from:

Combination 50% w/v Antifreeze (propylene glycol) 5% w/v Ethoxylatedtristyryl phenol phosphate 0.5% w/v (Soprophor FL) Nonyl phenol 9 moleethoxylate 0.5% w/v (Ethylan BCP) Sodium polycarboxylate 0.2% w/v(Sopropon T36) Attaclay (Attagel) 1.5% w/v Antifoam (Rhodorsil AF426R)0.003% w/v Water to 100 volumes

by stirring the above ingredients together and milling in a bead mill.

EXAMPLE C2

An emulsifiable concentrate is formed from:

Combination 20% w/v N-methylpyrrolidone (NMP) 25% w/v Calciumdodecylbenzenesulphonate 4% w/v (CaDDBS) (Arylan CA) Nonyl phenolethylene oxide propylene oxide condensate 6% w/v (NPEOPO) (SynperonicNPE 1800) Aromatic solvent (Solvesso) to 100 volumes

by stirring NMP, active ingredient, CaDDBS, NPEOPO and Aromatic solventuntil a clear solution is formed and adjusting to volume with Aromaticsolvent.

EXAMPLE C3

A wettable powder is formed from:

Combination 50% w/w Sodium dodecylbenzenesulphonate 3% w/w (Arylan SX85) Sodium methyl oleoyl taurate 5% w/w (Arkopon T) Sodiumpolycarboxylate 1% w/w (Sopropon T36) Microfine silicon dioxide 3% w/w(Tixosil 38) China clay 38% w/w

by blending the above ingredients together and grinding the mixture inan air jet mill.

EXAMPLE C4

A water dispersible granule is formed from:

Combination 50% w/w Sodium dodecylbenzenesulphonate 3% w/w (Arylan SX85) Sodium methyl oleoyl taurate 5% w/w (Arkopon T) Sodiumpolycarboxylate 1% w/w (Sopropon T36) Binder (sodium lignosulphonate) 8%w/w China clay 30% w/w Microfine silicon dioxide 3% w/w (Tixosil 38)

by blending the above ingredients together, grinding the mixture in anair jet mill and granulating by addition of water in a suitablegranulation plant (e.g. Fluid bed drier) and drying. Optionally theactive ingredient may be ground either on its own or admixed with someor all of the other ingredients.

The following non-limiting examples illustrate the invention.

EXAMPLE 1

Seed of various broad-leaf and grass weed species were sown in anon-sterilised clay loam soil. The soil surface was then sprayed withranges of combinations of either the individual herbicide or mixtures oftwo herbicides in various proportions, dissolved in a mixture of acetoneand water.

The said weeds are Amaranthus spinosus, Brachiaria plantaginea,Echinochola crusgalli, Eleusine indica, Sida rhombifolia, Digitariahorizontalis willd and Panicum miliaceum.

Two weeks after treatment the percent reduction in plant growth,compared to an untreated control, was assessed.

Control in one or more weed species was observed by combinations of thepresent invention.

EXAMPLE 2

Seed of the various weed species, as listed in Example 1, were sown andgrown up to a 1-3 leaves stage. Post-emergence applications with rangesof concentrations of either the individual herbicide or mixtures of twoherbicides in various proportions, dissolved in a mixture of acetone andwater were made.

Two weeks after treatment the percent reduction in plant growth,compared to an untreated control, was assessed.

Control in one or more weed species was observed by combinations of thepresent invention.

According to a further feature of the present invention there isprovided a product comprising a herbicidally effective amount of:

(a) a urea herbicide of formula (I); and

(b) 2-(2′-nitro4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione or anagriculturally

acceptable salt or metal complex thereof; as a combined preparation forseparate, simultaneous or sequential use in the control of weeds at alocus.

What is claimed is:
 1. A method for controlling the growth of weeds at alocus which comprises applying to the locus an effective amount of: (a)a urea herbicide, of the general formula (I): R¹¹N(R¹²)CON(R¹³)R¹⁴  (I)wherein R¹¹ represents an optionally substituted cyclic hydrocarbyl oraromatic heterocyclyl group, R¹² represents hydrogen or straight orbranched chain alkyl containing from 1 to 6 carbon atoms, R¹³ representsstraight or branched chain alkyl containing from 1 to 6 carbon atoms oran optionally substituted cyclic hydrocarbyl group and R¹⁴ representshydrogen or straight or branched chain alkyl or alkoxy containing from 1to 6 carbon atoms; and (b) a2-(2′-nitro-4′-methylsulfonybenzoyl)-1,3-cyclohexanedione or anagriculturally acceptable salt or metal complex thereof.
 2. A methodaccording to claim 1 in which compounds of general formula I are thosewherein R¹² represents the hydrogen atom or the methyl group and R¹³represents a phenyl or a methyl or a 3-trifluoromethylphenyl or4-chlorophenyl group and R¹⁴ represents the methyl group.
 3. A methodaccording to claim 1 in which compounds of general formula I are thosewherein R¹¹ represents a 4-chlorophenyl group or a3-chloro-4-methylphenyl or 3,4-dichlorophenyl or 4-isopropylphenyl groupand R¹⁴ represents a methyl or methoxy or butyl group.
 4. A methodaccording to claim 1 in which compounds of formula I are those whereinR¹¹ represents the benzothiazol-2-yl group, or a5-t-butyl-thiadiazol-2-yl; R¹² and R¹³ represent methyl and R¹⁴represents hydrogen.
 5. A method according to claim 1 in which (a) istebuthiuron.
 6. A method according to claim 1, wherein from 500 g to2500 g of (a) and from 10 g to about 500 g of (b) are applied perhectare.
 7. A method according to claim 1, in which the crop is a cerealcrop or sugarcane.
 8. A herbicidal composition comprising: (a) a ureaherbicide as defined in claim 1 and (b)2-(2′-nitro-4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione or anagriculturally acceptable salt or metal complex thereof, in associationwith a herbicidally acceptable diluent or carrier and/or surface activeagent.
 9. The composition according to claim 8 wherein the weight ratioof (a):(b) is from 1:1 to 5000:1.
 10. The composition according to claim8 wherein the weight ratio of (a):(b) is from 1:1 to 500:1.
 11. Aproduct comprising a herbicidally effective amount of: (a) a ureaherbicide as defined in claim 1; and (b)2-(2′-nitro-4′-methylsulfonylbenzoyl)-1,3-cyclohexanedione or anagriculturally acceptable salt or metal complex or mixture thereof; as acombined preparation for separate, simultaneous or sequential use in thecontrol of weeds at a locus.
 12. A method according to claim 1, wherein(a) is selected from the group consisting of isoproturon, chiortoluronand tebuthiuron, and (a) and (b) are applied to said locus incombination with a herbicide selected from the group consisting ofbifenox, diflufenican, diuron and ametryne.
 13. A method according toclaim 7, wherein (a) is selected from the group consisting ofisoproturon, chlortoluron and tebuthiuron, and (a) and (b) are appliedto said locus in combination with a herbicide selected from the groupconsisting of bifenox, diflufenican, diuron and ametryne.
 14. A methodaccording to claim 1 in which compounds of general formula I are thosewherein R¹¹ represents phenyl.
 15. A method according to claim 1 inwhich compounds of general formula I are those wherein R¹¹ representsthiadiazol-2-yl.
 16. A method according to claim 1 in which compounds ofgeneral formula I are those wherein R¹³ represents 2-methylcyclohexyl.